1. Field of the Invention
The assignee is the owner of several patents relating to ground tents, the foldable frames used in them, the hubs at the center of the frames and other features. Characteristic of these frames is a plurality of subframes each consisting of a central hub from which radiate foldable struts, generally four in number. The sides, top and rear wall of the tent are customarily provided with one such frame although in some designs, the side walls may include a second one arranged in end-to-end relation to the first. The front wall may also include such a frame, however, it is unnecessary since the side and rear subframes function in cooperation with one another and with the roof-supporting one to define a free-standing skeletal structure. The remote ends of these frames as well as the hub are connected to the sidewall and roof-forming portions of the skin such that the latter folds up inside the frame when the frame is collapsed. Sometimes this connection is formed by means of a cable connected between the strut ends which is then reaved through hems in the wall and roof panels or, alternatively, pockets formed in the corners of these panels which replace the cables.
A problem arises in keeping the skin panels taut, especially the wall panels. What causes this is the necessity for the struts to move from an essentially parallel nested relation in collapsed position, through a straight line relation and on beyond into an outwardly-bowed or obtuse-angular relation when fully extended into their operative wall-supporting position. Obviously, the diagonals of the rectangular wall surfaces defined by these struts in open position are longer when the struts occupy a straight line relation to one another than an angular or bowed one. The struts, while sometimes slightly bendable to the degree required for them to assume and maintain the aforementioned bowed relation are, nevertheless not so flexible as to keep from stressing the skin as they move through their straight line relation and on into an outwardly-bowed or obtuse-angular relation. What is needed, of course, especially with a fabric having little stretch, is to use a rather generous amount of material so as to not overstress and risk tearing it. Obviously, the net result is a skin panel that is not taut, will flap in the slightest breeze and is generally unsightly once the struts reach their fully extended outwardly-bowed or obtuse-angular relation.
2. Description of the Related Art
By way of background information, reference should be made to U.S. Pat. Nos. 3,810,482; 3,941,140; 4,026,312; 4,077,417; 4,285,354; 4,450,851; and 4,637,748, all of which relate generally to the aforementioned subject matter and are owned by the assignee. The closest prior art known to applicant is found in the U.S. Pat. Nos. to Harkness 2,869,561; McIlwaine 2,889,840; and Griesenbeck 4,590,956. The more than passing interest.